Abstract: The present disclosure discloses a method and device for removing iron in an iron-containing solution in hydrometallurgy. This method comprises the steps of: adding an iron-containing solution in hydrometallurgy into a reactor through a first homogenizing distributor, controlling concentration of the ferric iron in the reactor below 1 g/L, controlling pH of the solution in the reactor to be 2.5˜4, the temperature to be 65˜100° C., and the reaction duration to be 1˜3 hours, performing solid-liquid separation for the solution after reaction, and removing the iron in the iron-containing solution in hydrometallurgy in the form of goethite.

Abstract: The present invention addresses the problem of providing producing processes for garnet precursor microparticles (a precursor for microparticles of garnet structure) and microparticles of garnet structure. One of the processing processes comprises mixing ions of at least two elements with a basic substances that contain the at least two elements. The thin-film fluid is formed between at least two processing surfaces which are approachably and separably arranged facing each other with at least one of the processing surfaces rotating relative to the other. In the processing process, the precipitated microparticles are garnet precursor microparticles, and the molar ratio between the at least two elements in the garnet precursor microparticles is regulated by controlling the pH of the thin-film fluid after the mixing. Microparticles of garnet structure can be obtained by subjecting the garnet precursor microparticles to heat treatment.

Abstract: An apparatus (100) and process (400) for the treatment of wastewater and biological nutrient removal in activated sludge systems. The process uses substantially vertically downwardly presented inlet jets for delivering the incoming wastewater and recycled activated sludge into the body of liquid in a reactor, in a vertically downward direction and at a location just below the surface of the body of liquid. An effective circulating flow pattern of liquid is thereby established, along with optional concomitant entraining, dispersion or dissolving a fluid throughout the volume of the liquid body, facilitating a universal apparatus for mixing of anaerobic, anoxic, aerobic and oxic reactors or accommodating alternating said process conditions in one reactor. When an oxygen containing gas is entrained for aerobic fermentation, optimum gas bubble size is generated for efficient reaction with the digestion bacteria throughout the volume of the liquid body.

Abstract: There is provided a process for decontaminating and converting volumetrically contaminated radioactive metals, especially nickel, and recovering a decontaminated metal hydroxide or metal carbonate. The process includes the use of hydrogen peroxide to oxidize and remove nucleotides.

Abstract: This method is based in the recirculation of an iron free solution or a solution with low iron content in such a manner that the final acidity conditions obtained are ideal for iron to efficiently precipitate as jarosite. In a variation of the invention the zinc concentrate is subjected to the following stages: a. Roasting of at least part of the zinc concentrate. b. Neutral leaching where zinc oxide is dissolved. c. Acid leaching where zinc ferrites are leached. d. Reduction of the Fe+++ contained in the solution to Fe++ by adding zinc concentrate and diluting it with a zinc sulphate solution resulting from stage (f) to lower the concentration of Fe++. e. Neutralizing the acidity in the solution with calcine. h. Iron oxidation and jarosite precipitation, free of contaminating solids, by means of the injection of oxygen or oxygen-enriched air and the addition of an alkali or a Na+ o NH4+ salt.

Abstract: A process for recovering zinc from a zinc containing material, the process including the steps of: leaching the zinc containing material with an alkaline lixiviant comprising an aqueous mixture of NH3 and NH4Cl, or ionic equivalent, having a NH4Cl concentration of between about 10 g/L and about 150 g/L H2O and a NH3 concentration of between 20 g/l H2O and 250 g/L H2O, to produce a zinc containing leachate; stripping ammonia from the leachate to produce a stripped liquor which includes a zinc containing precipitate, the stripped liquor having a NH3 concentration of between 7 and 30 g/L H2O; and recovering the zinc from the stripped liquor.

Abstract: The present invention provides a process for preparing a solution of electrically uncharged [(OH)x(NH3)yZn]z where x, y and z are each independently 0.01 to 10, comprising at least the steps of (A) contacting ZnO and/or Zn(OH)2 with ammonia in at least one solvent in order to obtain a solution of electrically uncharged [(OH)x(NH3)yZn]z where x, y and z each independently 0.01 to 10 with a concentration c1, (B) removing some solvent from the solution from step (A) in order to obtain a suspension comprising Zn(OH)2, (C) removing solid Zn(OH)2 from the suspension from step (B), and (D) contacting the Zn(OH)2 from step (C) with ammonia in at least one solvent in order to obtain a solution of electrically uncharged [(OH)x(NH3)yZn]z where x, y and z are each independently 0.01 to 10 with the concentration c2, and to highly concentrated solutions of electrically uncharged [(OH)x(NH3)yZn]z where x, y and z are each independently 0.

Abstract: Provided is a method for producing an oxide and/or hydroxide wherein the ratio of oxide and hydroxide has been controlled. The method produces an oxide, a hydroxide, or a mixture thereof, and obtains an oxide and/or a hydroxide wherein the ratio of oxide and hydroxide has been controlled by means of changing a specific condition relating to at least one fluid to be processed introduced between processing surfaces (1, 2) when causing the precipitation of the oxide, hydroxide, or mixture thereof by mixing an basic fluid containing at least one type of basic substance and a fluid containing at least one type of metal or metallic substance as the fluids to be processed between the processing surfaces (1, 2) that are provided facing each other, are able to approach to and separate from each other, and of which at least one rotates relative to the other.

Abstract: A process for separating zinc from a feedstock containing a mixture of metals and metal compounds. The process includes leaching a zinc-containing feedstock with a concentrated basic solution, optionally diluting the slurry with an amount of water sufficient to reduce the viscosity of the slurry thereby facilitating separation of a pregnant liquor containing dissolved zinc from insoluble materials, separating the insoluble materials from the pregnant liquor, and precipitating zinc oxide from the pregnant liquor by adding an anti-solvent to the pregnant liquor. The described process also provides for recycling of the basic solution and the anti-solvent.

Abstract: Cd-112 isotope is recycled from a Cd-112 chemical separated solution or a remainder of an electroplating solution having a Cd-112 target. The present invention recycles Cd-112 isotope with a low cost, a high purity and a high recycle rate. The recycled Cd-112 isotope can be easily stored. And, the Cd-112 isotope can be used as an imaging agent in nuclear medicine.

Abstract: Disclosed is a method of manufacturing a metal oxide nano powder comprising preparing a first dispersed solution by adding a nano-sized metal powder to water and dispersing the metal powder within the water, performing a hydration reaction of the first dispersed solution at a temperature of about 30 to about 70° C. to generate a precipitation, and filtering and drying the precipitation to prepare a metal oxide powder. Also, disclosed is a metal oxide nano powder manufactured by the method described above, and having any one of a bar-form, a cube-form, and a fiber-form.

Abstract: Method for producing hydrometallurgical zinc oxide powder having characteristics equivalent to that derived from a French process, comprising formation of an aqueous pulp from a starting zinc oxide having particles of nodular structure, wet milling of this aqueous pulp, separation in this milled pulp between a liquid phase and a solid phase containing the zinc oxide, and drying of said solid phase, coupled with a mechanical deagglomeration of the particles during drying, to obtain a dry zinc oxide powder with particles of nodular structure having a particle size distribution where the particles have an average size (d50) between 0.02 and 20 ?m.

Abstract: A method of treating alkaline industrial by-products, such as red mud generated by Bayer process bauxite refining, is described. Embodiments of the method comprise treating the alkaline industrial by-products with salts of divalent and/or polyvalent cations, thereby lowering pH of the alkaline industrial by-products. The method involves replacement reactions in which relatively insoluble hydroxide salts form precipitates, thereby removing hydroxide ions from solution.

Abstract: Disclosed are metal phosphate sols made by mixing at least one metal oxide, at least one phosphate precursor, at least one organosilane, and a liquid. Also disclosed are nanocomposites containing the metal phosphate sols and at least one of metal nanoparticle and metal-chalcogenide nanoparticle. The nanocomposites containing metal nanoparticles may be chalcogenized to provide nanocomposites containing metal-chalcogenide nanoparticles. Also disclosed are composites containing a dielectric material such as a polymer and at least one of the metal phosphate sol and the nanocomposite.

Abstract: A hydrometallurgical process utilizing an atmospheric calcium chloride leach to selectively recover from various metal feed stocks (consisting of elemental metals, metal oxides, metal ferrite, metal hydroxide, metal carbonates, metal sulfate/sulfur compounds, and their hydrates, specifically including but not limited to EAF Dust K061) zinc, lead, cadmium, silver, copper and other valuable metals to the exclusion of iron, magnesium, halogen salts and other unwanted elements. The process solves the problem of iron and magnesium leach solution contamination because iron is unexpectedly converted to magnetite. The heavy metals are cemented out of solution using zinc or other selected dust at a pH of 6 or greater under unique and unexpected conditions, which do not require acid.

Abstract: A nanoporous reactive adsorbent incorporates a relatively small number of relatively larger reactant, e.g., metal, enzyme, etc., particles (10) forming a discontinuous or continuous phase interspersed among and surrounded by a continuous phase of smaller adsorbent particles (12) and connected interstitial pores (14) therebetween. The reactive adsorbent can effectively remove inorganic or organic impurities in a liquid by causing the liquid to flow through the adsorbent. For example, silver ions may be adsorbed by the adsorbent particles (12) and reduced to metallic silver by reducing metal, such as ions, as the reactant particles (10). The column can be regenerated by backwashing with the liquid effluent containing, for example, acetic acid.

Abstract: A method for the preparation of nano size zinc oxide particles having an average primary particle diameter of less than or equal to 15 nm, which are redispersible in organic solvents and/or water, by basic hydrolysis of at least one zinc compound in alcohol or an alcohol/water mixture. The hydrolysis is carried out with substoichiometric amounts of base, based on the zinc compound. The precipitate which originally forms during hydrolysis is left to mature until the zinc oxide has completely flocculated. This precipitate is then thickened to give a gel and separated off from the supernatant phase.

Abstract: Process for the manufacture of an aqueous sodium chloride solution, according to which a solid material comprising sodium chloride and heavy metals is dispersed in water, the aqueous medium thus obtained is alkalinized so as to precipitate the heavy metals in the form of metal hydroxides, calcium carbonate is coprecipitated with the metal hydroxides in the aqueous medium and the aqueous medium is then subjected to mechanical clarification.

Abstract: An apparatus and a process for producing zinc oxide from a zinc-bearing material are provided. The process comprises the steps of leaching the complex sulfide material with hydrochloric acid, ferric chloride, and oxygen; precipitating iron from the leach solution using lime and oxygen; removing copper, silver, cadmium, cobalt and lead from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using lime; and regenerating HCl from a calcium chloride leach filtrate solution to regenerate hydrochloric acid and precipitate gypsum. Related processes for recovering copper, silver, lead, and iron from complex sulfide materials and for recovering lead from residue by solubilizing lead chloride and precipitating it with lime are also provided.

Abstract: The present invention relates to an apparatus and a process for producing zinc oxide from a zinc-bearing material. The process according to the present invention comprises the steps of leaching the complex sulfide material with hydrochloric acid and oxygen; precipitating iron from the leach solution using magnesium oxide and oxygen; removing copper, silver, cadmium, cobalt and lead from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using magnesium oxide; and spray roasting the remaining magnesium chloride leach solution to regenerate hydrochloric acid and magnesium oxide. The present invention further relates to processes for recovering copper, silver, lead, and iron from complex sulfide materials.

Abstract: A method for the total precipitation of valuable metals, such as copper, nickel, zinc, cobalt, etc., from a leaching solution that has been acidified with sulphuric acid and that is substantially free from impurities, by neutralizing the solution with lime and/or limestone. Neutralization is effected in at least two stages, wherewith only partial precipitation is effected in the first stage, and wherewith full precipitation of remaining valuable metal content is effected in the last stage, by adding a surplus of neutralization agent. Slurry containing precipitates and remaining solid neutralization agent formed in the last stage in the neutralization process is returned to the first neutralization stage, possibly after re-dissolving the slurry in the incoming acid leaching solution. The amount of slurry returned together with any further neutralizing agent added promotes the partial precipitation of the valuable metal content.

Abstract: The invention relates to a method for recovering non-ferrous metals, particularly nickel, cobalt, copper, zinc, manganese and magnesium, from materials containing said metals by converting said non-ferrous metals into sulphates by means of melt and melt coating sulphation, i.e. by a thermal treatment under oxidizing conditions within a temperature range of 400 to 800° C., during which a reaction mixture is formed containing at least one said non-ferrous metal, iron(III)sulphate and alkali metal sulphate, and appropriate reaction conditions are selected to substantially prevent iron(III)sulphate from thermally decomposing to hematite, and finally, said non-ferrous metals are recovered as metallic compounds. In the method of the invention, a process is formed around the melt and melt coating sulphation, which comprises nine steps.

Abstract: The invention provides a process for the removal and recovery of zinc from an aqueous process stream. In particular, the process of the invention is useful in the removal and recovery of zinc compounds such as zinc chloride from an aqueous effluent stream produced in various manufacturing processes such as the manufacture of sorbic acid.

Abstract: This invention relates to synthetic chalcoalumite-type compounds represented by formula (1) below:M.sup.2+.sub.a-x/2 Li.sub.x.sup.1+ Al.sub.4.sup.3+ (OH).sub.b (A.sup.n-).sub.c.mH.sub.2 O (1)(whereinM.sup.2+ represents at least one of the following divalent metal ions: Zn.sup.2+, Cu.sup.2+, Ni.sup.2+ and Mg.sup.2+,a is 0.6<a<1.2,x is 0<x<1.4,b is 11<b<13,A.sup.n- is at least one member of the group consisting of SO.sub.4.sup.2-, HPO.sub.4.sup.2-, CO.sub.3.sup.2-, SiO.sub.3.sup.2-, SO.sub.3.sup.2-, HPO.sub.3.sup.2-, H.sub.2 PO.sub.4.sup.-, NO.sub.3.sup.- and OH.sup.-,c is 0.5<c<1.2, andm represents a number of 1 to 4)and processes for their preparation. The synthetic chalcoalumite-type compounds of the present invention are conveniently used for adsorbing agents of acidic substances, anion exchangers, infrared absorption agents for agricultural films, deodorants and recording media for ink jet, etc.

Abstract: An aqueous system for the production of metal chalcogenide nanocrystalline salts such as zinc selenide, from a hydrolyzable chalcogen carbonyl compound, such as selenourea, by simple hydrolysis thereof under alkaline conditions in the presence of water soluble metal hydroxide, such as zinc hydroxide in the form of the zincate ion, i.e., Zn(OH).sub.4.sup.-2. Selenourea contains selenium in the correct oxidation state, is inexpensive, commercially-available and readily hydrolyzable under aqueous basic conditions in the presence of the zincate ion to form zinc selenide. The zinc selenide is insoluble in the alkaline aqueous vehicle and precipitates over time in the form of nanocrystallites or quantum dots of the zinc selenide.

Abstract: For the removal of heavy metal contaminants from industrial waste water, a method is proposed for preparing a dense precipitate having superior handling and disposal properties. The method comprises incremental adjustment of the pH to maintain a low saturation ratio and recycling of slurry to provide seed crystals for secondary nucleation.

Abstract: A mercury-free dissolution process for aluminum involves placing the aluminum in a dissolver vessel in contact with nitric acid-fluoboric acid mixture at an elevated temperature. By maintaining a continuous flow of the acid mixture through the dissolver vessel, an effluent containing aluminum nitrate, nitric acid, fluoboric acid and other dissolved components are removed.

Abstract: There is disclosed a method of treating a solution, e.g., an alkaline or acidic solution, containing heavy metals ions therein. With respect to alkaline solutions, the method includes providing a body of the solution; contacting the body with a material such as carbon dioxide to change the pH, e.g., to lower the pH to a pH in the range of 9 to 10.5; then treating the solution to further change the pH and cause precipitation of hydroxides, including chromium hydroxide; and separating the hydroxide precipitates from the solution to provide a substantially neutral solution having a reduced amount of chromium ions, for example, contained therein.

Abstract: A zinc- and lead-containing residue from a metallurgical plant is reprocessed by a thermal treatment in a circulating fluidized bed system. A major part of the heat demand is satisfied by a combustion of solid carbonaceous material in the fluidized bed reactor of the circulating fluidized bed system. A reducing fluidizing gas, which is virtually free of free oxygen, is fed to the lower part of the fluidized bed reactor. A solid carbon content of from 5 to 30% is adjusted in the fluidized bed in the lower portion of the fluidized bed reactor, which is supplied in its upper portion with oxygen-containing gases and in which CO.sub.2 is formed only at such a rate that zinc metal is not reoxidized. Substantially all solids are removed in a recycling cyclone from the suspension discharged from the reactor and the removed solids are recycled. The gas is cooled to a temperature at which zinc metal is oxidized to ZnO. The dust-like zinc compounds and lead compounds are removed from the gas.

Abstract: A method for manufacturing a precursor powder for use in making a varistor is disclosed. This precursor powder is produced by preparing a homogeneous aqueous dispersion of metal oxides and/or metal hydroxides and heating the dispersion in a closed pressure reactor to a temperature between 200.degree. C. and 350.degree. C. for hydrothermally treating the homogeneous dispersion. The precursor powder produced in the afore-described method is highly homogeneous and of controlled crystal phase and morphology and after mixing with zinc oxide powder can homogeneously be reacted with the zinc oxide in a ceramic process.

Abstract: A process for separately removing zinc and iron from acidic wastewater. The process involves adding alkali metal hydroxide to the acidic wastewater (below about pH 4) to achieve a first pH of about 4.8 to at most about 5.4 and precipitate an iron hydroxide-containing precipitate at this pH. The precipitate from the wastewater is separated and then additional alkali metal hydroxide is added to achieve a second pH in the range from about 8.8 to about 9.4. A zinc hydroxide containing precipitate forms at this second pH and is then recovered by filtration.

Abstract: The chromic anhydride contained in soluble form (chromic acid) in exhausted, polluted chromium plating baths is recovered by alkalizing the exhausted chromium plating liquid to a pH comprised between 3 and 7 at a temperature of 70.degree. C. with a commercial sodium hydroxide solution, keeping the mass in reaction at this temperature for an hour and filtration separating the precipitate obtained. The filtered solution having a specific gravity of 1.25 kg/l, contains CrO.sub.3 (22% in weight) which is then reduced with sulphur dioxide to obtain a solution containing basic chromium sulphate and sodium sulphate, suitable for use as a tanning bath; in this manner pollution is avoided and the waste chromium is exploited. The solution containing CrO.sub.3 can also be introduced into a hexavalent chromium salt production cycle.

Abstract: The present invention provides a process for easily preparing .gamma.-Cd(OH).sub.2. The present invention facilitates improvement in the charge/discharge performance and energy density of an alkaline secondary battery having a cadmium electrode including .gamma.-Cd(OH).sub.2. The present invention provides superrapid-chargeable batteries, such as a nickel-cadmium alkaline secondary battery having a cadmium electrode including .gamma.-Cd(OH).sub.2 in which the weight of cadmium hydroxide contained in the negative electrode is 0.95 times as much as the weight of nickel hydroxide contained in the positive electrode, a manganese dioxide-cadmium alkaline secondary battery in which the weight of cadmium hydroxide contained in the negative electrode is not more than 0.84 times as much as the weight of manganese dioxide contained in the positive electrode, and a silver oxide-cadmium alkaline secondary battery in which the weight of cadmium hydroxide contained in the negative electrode is not more than 1.

Abstract: A process for treatment of incinerator ash typically including heavy metals and both water soluble and insoluble fractions. The insoluble fraction is first removed from the fly ash. The soluble fraction is treated to precipitate heavy metal compounds. Preferably, the heavy metal precipitates are incorporated in a vitrifiable batch. In a separate vitrifiable batch, the insoluble fly ash portions may also be incorporated. Most preferably, bottom ash from the incinerator is also incorporated in a glass batch. The bottom ash glass batch may also incorporate the insoluble fraction from the fly ash.Precipitation of the heavy metal constituents in the soluble portion of the fly ash is preferably accomplished by raising the pH of the solution, most preferably above 10 by addition of alkali metal or alkaline earth metal hydroxides.

Abstract: A process for obtaining available elements from seawater is described, which process includes two separation steps. The first separation step involved adjusting the pH of seawater to a low pH by adding a strong acid having sulphate ion, adding a strongly alkaline agent thereto in amount sufficient to provide a high pH and separating the precipitate formed thereby from the filtrate. The second separation step involves concentrating the filtrate, cooling the concentrated filtrate and separating a precipitate thereby formed. Each precipitate and each filtrate obtained in these steps has characteristic components and can be utilized for many purposes, for example, for food additives, as a solvent for paint, as combustion aids, or as alkaline agents for neutralization etc.

Abstract: Metal values are separated from arsenic sulfide ores in a hydrometallurgical oxidation process using a balanced reactant slurry. The molar concentration of As and Sb in the reactant slurry is controlled with respect to the molar concentration of Cu, Pb, and Zn in the slurry so that, upon reacting, soluble arsenic compounds or toxic arsenic vapors are not formed.

Abstract: A process for pretreatment at high temperature by means of an aqueous pretreatment solution, of crushed ores containing at least one usable metal element, whose gangue contains argillaceous compounds which, in the attack operation for making use of the ore, are capable of forming a stable plastic suspension in the presence of water, which makes it virtually impossible subsequently to separate the liquid and solid phases by virtue of its character being such that it cannot be subjected to filtration and/or settlement, which is characterized in that, to cause stabilization of the argillaceous gangue before the operation of subjecting the ore to attack and to produce easy separation of the liquid and solid phases after the attack operation, the ore, the granulometry of which is at most equal to the liberation sieve mesh size of the metal or metals to be put to use, and before being subjected to the attack operation for making use of the ore, is brought into contact with an aqueous pretreatment solution containin

Abstract: In a hydrometallurgical process of treating zinc-laden dust issuing from electric steel plant furnaces the zinc-laden dust is subjected to a basic leaching or lixiviation in two steps. The dust is subjected to a first leaching of the zinc oxide with a relatively low concentration of caustic soda, then to a second leaching of the zinc ferrite with a higher concentration of caustic soda, then the zinc is extracted from the solution obtained by this basic leaching.

Abstract: A process for recovering cobalt and nickel values from cobalt and nickel containing sulphidic material also containing iron includes roasting the sulphidic material to produce a calcine containing water soluble cobalt and nickel sulphate, and leaching the calcine in aqueous sulphate solution under oxidizing conditions at an oxygen overpressure in the range of from about 50 kPa to about 1500 kPa and at a temperature in the range of from about 100.degree. to about 180.degree. C. to produce an iron-containing residue and a cobalt and nickel containing solution. The residue is separated from the solution, and cobalt and nickel values are recovered from the solution.

Abstract: A hydrometallurgical process is provided for separative treatment of zinc-bearing metallurgical flue dust containing significant amounts of lead, chlorine, and iron. The process is especially suited for extraction of zinc sulfate from blast furnace white dust resulting in the smelting of secondary copper. According to the process, the flue dust is leached in sulfuric acid solution for substantially complete dissolution of soluble constituents, notably zinc, leaving insoluble residue consisting principally of lead oxide. At completion of leaching, pH is selectively adjusted corresponding to the desired extent of subsequent chloride removal. Second, the loaded leach solution is treated for chloride removal wherein chloride ion concentration is substantially and selectively reduced by precipitation of cuprous chloride, cuprous ions being provided by pH regulated reduction of cupric ions.

Abstract: The invention relates to a process for the removal of heavy metal ions, particularly chromium, lead and/or zinc ions, from aqueous liquids by precipitation wherein the aqueous liquid containing the heavy metal ions and an aqueous liquid containing a base which precipitates the heavy metal ions in the form of their hydroxide or basic salt are added simultaneously to an amount of water at a pH between 5 and 10 and a temperature between 60.degree. and 100.degree. C. and the pH and the temperature are maintained in the specified ranges during the precipitation.

Abstract: A process for the removal of iron and aluminum values from acidic solutions thereof with zinc chloride wherein the solution is subjected to pressure hydrolysis to precipitate the iron and aluminum as the hydroxides or oxide hydrates, and then the precipitate is removed and washed. Zinc chlorides which are particularly free from iron and aluminum can be rapidly and easily obtained with this process.

Abstract: A process for treating zinc sulphide materials wherein the sub-divided material is firstly leached, at less than 119.degree. C., with a sulphate leach solution, low in sulphuric acid and having a high iron content together with zinc and impurities in a manner causing iron to precipitate and subsequently leaching the residue and re-dissolving the iron precipitate with spent electrolyte containing regenerated sulphuric acid resulting from the treatment of the leach liquor obtained from the first leach step and wherein the leach solution from the subsequent leach step constitutes the starting leach solution for the first leach step.

Abstract: A process of regenerating and recovering lead from lead sulphate-containing wastes which comprises(i) contacting the lead battery scrap with an aqueous solution of ammonium carbonate to form lead carbonate and ammonium sulphate,(ii) subjecting the solid phase containing the lead carbonate obtained by solid-liquid separation of the reaction product so formed to roast-reduction at a temperature ranging from about 350.degree. C. to about 700.degree. C. in the presence of a carbon material reducing agent to generate and recover the lead,(iii) double decomposing the liquid phase containing the ammonium sulphate obtained by said solid-liquid separation by the addition of calcium hydroxide in an amount such that the molar ratio of the calcium hydroxide added, expressed as Ca(OH).sub.2 /(NH.sub.4).sub.2 SO.sub.4, is about 1.05 to about 1.

Abstract: This invention relates to stable, fluid zinc-containing dispersions and the preparations thereof by the high temperature decomposition of ZnCO.sub.3 to ZnO in a dispersant-containing fluid.

Abstract: Process for purifying an iron containing zinc sulfate solution which comprises precipitating iron from said solution as a slurry in at least one of the following forms at a pH which is maintained lower than 4: basic sulfate, jarosite or goethite; filtering said slurry on a planar horizontal filter and forming a cake on said planar filter; washing the cake directly on the planar filter with water supplied onto the cake without forming a newslurry with washing water and thus freeing the cake from water soluble zinc and copper compounds promptly before hydrolysis thereof insolubilizes said compounds as basic sulfates, whereby the solid residue in the cake does not contain substantially more insoluble zinc content than it contained in the slurry being fed to the filtration.

Abstract: Zinc is recovered from a material containing zinc and iron. The material is leached with sulphuric acid to produce a final pH of 3-5.5. Zinc powder is added to the leaching solution to precipitate polluting metals. Zinc is now extracted with a solution of a dialkyl phosphoric acid in an organic solvent. Zinc is extracted from the organic solution with sulphuric acid. Zinc is recovered from the sulphuric acid solution as metal or as zinc sulphate.

Abstract: A process for the re-utilization of the sulphate residues from the electrolytic treatment of zinc.The residues are digested hot with concentrated HCl in the presence of CaCl.sub.2. PbCl.sub.2 crystallizes on cooling. FeCl.sub.3 is extracted with TBP circulating in the direction of a series of columns and FeCl.sub.3 is extracted in a first column, washed in a second column and re-extracted a third column. The solution which issues is treated with NH.sub.3, resulting in precipitation of the majority of the hydroxides of the metals contained therein, which are subsequently separated, while Ag, Zn and Cu are complexed. Ag is precipitated with (NH.sub.4).sub.2 S.NH.sub.3 is recovered by means of lime. CaCl.sub.2 is re-cycled to the start of the process and Cu and Zn are leached together with the mineral.Application of the process to the recovery of the metals contained in the residues from the digestion of blends.

Abstract: There is disclosed a process for separating iron, zinc and lead from flue dust and/or flue sludge, wherein the three following reaction stages are performed in the aqueous phase:A. Oxidation of the iron and filtration of the resulting first turbid liquid;B. Suspension and acidification of a first filtration residue and subsequent filtration of the resulting second turbid liquid, whereby a second filtration residue containing mainly iron sludge is obtained;C. Neutralization of the filtrate and subsequent filtration of the resulting third turbid liquid, whereby a third filtration residue containing the precipated heavy metals is obtained.

Abstract: A process for the recovery of metal values, principally zinc and copper, from an aqueous acidic purge stream in a hydrometallurgical process by contacting the stream containing the iron, copper and zinc sulfates, along with trace amounts of other metallic sulfates with calcium oxide to bring the pH in the range 3.0-4.0, thence with sufficient ammonia to form the soluble tetrammine sulfates of copper and zinc, then separating the copper from the zinc, e.g. by hydroxy oxime-solvent extraction and thereafter recovering the zinc as zinc oxide by converting the zinc tetrammine sulfate to the hydroxide and removing ammonia from the complex.